1. Field of the Invention
This invention pertains to a dynamic radiation monitor, and in particular, a dynamic radiation monitor that determines, at any given time, the amount of time a person has at a particular location until receiving a pre-selected maximum permissible radiation exposure.
2. Description of Related Art
Monitoring radiation levels is advantageous in a number of different environments. For example, in the nuclear power industry, the exposure of people to occupational radiation must be monitored in order to protect their health. In normal operation, this problem has been solved with relatively simple and inexpensive devices.
In other situations such as in the case of a radiation leak which requires clean-up operations, or nuclear or dirty bomb detonation, the radiation levels to be encountered are not easily predicted, and these levels would likely be much higher than those encountered in the more normal situation. The higher radiation levels mean that an individual's exposure can rapidly approach safe limits. Therefore, it is important to have a device capable of calculating and displaying in real time the radiation dose, dose rate, as well as the allowable stay time, in addition to providing visual and/or audio alarms that are readily and reliably relied to the operator
Radiation monitors which indicate whether a biological organism, such as a person, has been exposed to radiation are well known. For example, U.S. Pat. No. 4,642,463 (Thoms) issued Feb. 10, 1987 and entitled INTELLIGENT RADIATION MONITOR, which is incorporated herein by reference in its entirety, discloses a radiation monitor having a processor and display for detecting and signaling real time radiation rates.
U.S. Pat. No. 5,572,027 (Tawil et al.) issued Nov. 5, 1996 and entitled INTEGRATED DOSIMETER FOR SIMULTANEOUS PASSIVE AND ACTIVE DOSIMETRY, which is incorporated herein by reference in its entirety, discloses a radiation monitoring system using paired active and passive radiation detectors to monitor radiation exposure. The active detector has a processor to monitor the radiation rate and dose level, and has a LCD display for indicating the dose and/or dose rate.
U.S. Pat. No. 6,031,454 (Lovejoy et al.) issued Feb. 29, 2000 and entitled WORKER SPECIFIC EXPOSURE MONITOR AND METHOD OF SURVEILLANCE OF WORKERS, which is incorporated herein by reference in its entirety, discloses a radiation monitor that tracks radiation doses in real time.
The above mentioned devices, however, do not process the detected radiation data in form that is convenient or desirable to the user. The vast majority of first responders to a radiation event will likely not be experts in radiation detection technology or radiation safety. Even if they have received training, they will likely not remember the significance of the various radiation units displayed by current generation meters and dosimeters. These first responders need to be able to stay focused on their area of expertise (e.g., fire-fighting, rescue operations, emergency medical treatment, crowd control, forensics, etc.). When responding to the scene, the following factors are generally of paramount interest to the responder: radiation levels with respect to normal background, time left to work safely; safety of some locations with respect to others, significant changes in the radiation hazard environment, and when to leave the area.
Therefore, an objective of the present invention is to provide a real-time radiation monitor that is programmable to allow for quick and identifiable communication of critical information that is of interest to the responder.